1. Field of the Invention
The present invention generally relates to fendering devices and, more particularly, to an inflatable fendering apparatus capable of stable operation while absorbing kinetic energy in order to prevent damage to watercraft and marine structures.
2. Description of the Prior Art
Fendering systems are used to absorb the kinetic energy of watercraft during berthing operations and to provide a safe minimum standoff distance between moored vessels and other marine structures such as docks, piers, and the like. The principal function of fendering systems is to prevent damage caused by direct contact of the watercraft's hull to other watercraft, docks, piers, and the like. In particular, berthing forces can result in impact and abrasion damage to a watercraft's hull or other marine structures.
Many types of watercraft fender designs (including inflatable and resilient systems) are known to those skilled in the art. The problem with these types of fenders is that the fenders do not provide a reasonable standoff distance for large watercrafts and the fenders do not absorb a significant magnitude of berthing kinetic energy. In addition, during a rough sea state, these fenders are not stable and may swing significantly so that their function could be compromised. Furthermore, these fenders require a large space for stowing and storage since many cannot be deflated after use.
The following patent references describe various prior art systems that may be related to the above and/or other bumper and fender devices:
U.S. Pat. No. 6,161,494 teaches an inflatable apparatus that is located on the hull of a boat, and means for inflation and deflation of the inflatable member. The disadvantage of this apparatus is that the height of the apparatus is not adjustable to the water level and may not be effective if the water level is different than that of the fender's location on the hull. In addition, this apparatus is not suited for retrofitting to other boats because the apparatus requires structural changes to the boat.
U.S. Pat. No. 5,357,888 teaches an inflatable apparatus that is attached to the hull of a boat in a longitudinal direction. Similar to the previous cited reference, the disadvantage of this apparatus is that the apparatus is fixed in location and does not float with the water level. Also, the apparatus requires modification of the hull structure.
U.S. Pat. No. 4,815,777 teaches a trim guard assembly apparatus with a flexible member and a hollow closure which may be filled with a fluid or emptied. The trim guard assembly apparatus is used in combination with a vehicle body having an outer protective member, an inner base member, and a flexible, intermediate substantially hollow closure provided therebetween. The hollow closure may be selectively filled with or emptied of a fluid, thereby respectively expanding or retracting the protective member. In use, when in a parked position, the protective member is expanded thereby absorbing minor impacts such as outswung doors, protected shopping carts and the like. When the vehicle is in motion, the protective member is retracted; thereby, re-achieving aerodynamic streamlining of the automotive vehicle. The disadvantage of this apparatus is that the standoff distance is limited and requires structural modification of the hull.
U.S. Pat. No. 4,970,980 teaches a side protector similar to the previously cited reference which may be affixed to the hull of a watercraft having an inflatable bladder. The protectors are modularized and a plurality of the protectors may be affixed to the craft along either horizontal rows or individual protectors may be vertically orientated, depending on the anticipated need for protection. A snap-lock type connection, including mating extensions and recesses in a chamber closed at one end, is provided for affixing the bladder edges to the base holder. A space is left between the legs of bladder connector so that when high pressure air is added to cause inflation of the bladder, the same air also creates additional pressure maintaining the bladder coupled to the base. An air compressor and operator's panel are provided which permits any of the various bladders to be inflated depending on the particular need at the particular time. In addition, the bladder contains a setoff in the interior thereof to maintain the bladder spaced apart from the holder mechanism to prevent flapping, as well as to provide additional strength at the point of contact of the inflated bladder with the hard object against which protection is desired. A disadvantage of this device is that it is fixed to the hull and is therefore independent of the water level.
U.S. Pat. No. 4,841,893 teaches a cylindrical fender with rings to prevent the fender from popping up between the side of a watercraft and corresponding dock or other structure to which the craft is tied off. The circumferential rings prevent the fender from popping up from between the side of a boat and a corresponding dock or other structure to which the boat is tied off, with the circumferential rings providing for a rolling and tracking motion of the fender over the side of the boat to limit fender swing which maintains the fender in place and in a generally vertical orientation. This tracking prevents the non-tethered end of the fender from popping up. The disadvantages of this fender are that it does not teach the deflation or storage of the fender and is applicable only for small watercraft.
U.S. Pat. No. 5,215,031 also teaches a protective device for a watercraft with rigid hull that is inflatable and structurally fixed to the hull. The device consists of a first inflatable bumper mounted to the rigid hull about the gunwale, which will absorb impacts to the hull when the boat is pulled next to a dock or the like. A second inflatable bumper is mounted to the rigid hull at the waterline to keep the rigid hull afloat if it becomes cracked. A mechanism is in the cockpit for selectively inflating the first inflatable bumper and the second inflatable bumper. The same above-mentioned disadvantages apply to this patent.
The above-cited prior art does not disclose fendering devices which provide reasonable standoff distances between watercraft and/or the capability to safely absorb the kinetic energies associated with berthing watercraft and larger ships. Therefore, there is a continuing need for a reliable fendering system for watercraft and large ships in which the fendering system is inflatable; deflatable; rapidly deployable; able to absorb significant kinetic energies; dynamically stable in rough sea states; designed for minimal stowage volume and used to provide minimum standoff distance between watercraft and other marine structures.